This invention relates to electrical connectors and, more particularly, to hermetically sealed electrical connectors for use in passing electrical conductors through a bulkhead while simultaneously isolating high pressure on one side of the bulkhead from low pressure on the other side of the bulkhead.
Various structures have been developed as electrical connectors to allow ready attachment and detachment of wires between electrical devices. Many electrical connectors include a plug and a receptacle. The plug includes one or more electrically conductive male contacts or pins, and the receptacle includes a like number of female electrically conductive contacts. Either the male contacts, the female contacts, or both are permanently electrically connected to wires or leads. Either the plug or the receptacle is mounted in a wall or secure structure, such as a bulkhead, although in some instances both the plug and the receptacle will be connected to one another independently of any other structure. Electrical connection is easily achieved by pushing the male contacts on the plug into the receptacle (or vice versa), and disconnection is achieved by pulling the plug out of the receptacle. Such components are often mated with other components such as socket blocks or sealed connector boot assemblies. Where the connector is situated within a bulkhead, the connector is essentially the main component and attachment to each of the exposed ends of the conductors of the connector could be accomplished either by direct and permanent connection to egress leads or by removable connections as described above.
Generally the electrically conductive contacts of both the plug and the receptacle are supported in a dimensionally stable, electrically insulative material surrounded by a metallic housing or similar rigid structure. This insulator electrically isolates the various contacts and further maintains alignment of the contacts for ready connection and disconnection and to maintain electrical isolation from the housing and the bulkhead, if any. Metal housings are often used to provide greater support for the connector, and are particularly useful in settings where high forces will be encountered by the connector. Notwithstanding the advantages of using housings, such structures can have significant drawbacks, including the cost of making the housings and incorporating the housings into the connector.
Moreover, in certain settings it is desired that either the plug or receptacle be “hermetically” sealed, i.e., sealed so as to prevent egress of fluids across a boundary created by the seal. Hermetically sealed connectors are particularly useful when it is necessary to maintain a controlled environment on one or both sides of the connector, and specifically where the integrity of electrical power or an electrical signal must be maintained between a region of relatively high pressure from a region of relatively low pressure. Hermetic connectors have particularly great utility in the field of downhole well tools used for subterranean drilling operations, where temperatures can exceed 500 degrees Fahrenheit and pressures can reach above 30,000 pounds per square inch. In such settings, various electronic components are housed within the downhole well tools and such electronics generally are designed to operate at atmospheric pressure, thereby requiring effective isolation between the high pressures of the ambient environment within the well and the low or atmospheric pressure within electronics modules. Additionally, it is generally required that electrical leads pass from within the sealed well, at high pressure, to the ambient conditions above ground to provide for control and monitoring within the well. Accordingly, for both conditions, hermetic connectors are essential to the functioning of downhole well tools.
Hermetic connectors for high temperature and high pressure service are known in the prior art, for example the invention described by U.S. Pat. No. 6,582,251 (Burke et al., “the '251 patent”). The invention of the '251 patent eliminates use of a housing in the construction of an electrical connector thereby eliminating a potential leak path between the insulator and the housing. Similar to the present invention, the invention of the '251 patent comprises electrical conductors embedded in polymeric materials. One limitation of the invention of the '251 patent is that at extreme pressures and temperatures (e.g. 30,000 psi and 500 deg F.), the connector polymeric materials are subject to creep and movement of the conductor pins can subsequently occur, resulting in unacceptable levels of reliability of the '251 patent connector at these extreme conditions.
The connector of the present invention provides improved reliability at extreme pressure and temperature conditions, while preventing pressure or electrical leakage. It can be used in a high temperature environment wherein high pressure differential exists and there is a need to protect electronics or other electrical or mechanical assemblies from exposure to undesirable higher or lower pressures than those at which they were designed to operate, and where electrical power or signals must be passed across the boundary between high and low pressure.